To obtain a dehumidifying capacity in proportion to the number of dehumidifying cylinders by equalizing the loads of the cylinders with the occupying area of a dehumidifier for compressed air reduced.

In a dehumidifier in which dehumidifying cylinders 10, each of which consists of a pressure container, is equipped with an air introduction pipe 21 and an air discharge pipe 31, and removes water in compressed air, are overlapped vertically, the sets of the air introduction pipes 21 and the sets of air discharge pipes 31 are connected in parallel with a main air introduction pipe 20 and a main air discharge pipe 30 respectively, and compressed air is passed through the dehumidifying cylinders 10, the main air introduction pipe 20 and the air introduction pipes 21 are branched and connected through a water drop storage tank 4.